1. Technical Field
This invention relates in general to household kitchen appliances, and more particularly to electric appliances used to make toast, such as toasters and toaster ovens.
2. Discussion
Conveyor ovens typically include an oven housing, a heat source within the housing, and a conveyor configured to move food products through the oven, whereby the food products are heated or toasted by the heat source. The use of an endless conveyor to move food products through the oven typically increases the processing capacity of conveyor ovens over other types of ovens. The degree to which food products are heated depends on the temperature within the conveyor oven and the time period during which food products are heated (which is a function of conveyor speed). Thus, to control the degree of heating, conveyor ovens typically provide operator controls configured to adjust the oven temperature or conveyor speed.
Different types of conveyor ovens are known. For example, conveyor toasters are commonly used to toast food products including bread, buns, bagels, muffins and waffles. These conveyor toasters, which include both vertical and horizontal models, include a toaster housing, electric heating elements mounted within the toaster housing, and an endless conveyor which moves food products adjacent to the heating elements such that the food products are toasted. The food products can be placed directly on the conveyor of a horizontal toaster oven, or can be held within a food-carrying basket of either a vertical or horizontal toaster oven. Food products are manually loaded through an opening in the housing, are toasted as they are moved past the heating elements by the endless conveyor, and are discharged into a product receiving tray located at the bottom of the housing.
Other types of conveyor ovens for processing food products include, for example, conveyorized pizza ovens, microwave ovens and tunnel ovens. Control over the degree of heating in each type of conveyor oven is typically accomplished by varying the oven temperature or the conveyor speed. Although the description below is focused on toaster conveyor ovens, the term "conveyor oven" is intended to include other conveyor oven types.
In some conveyor ovens, conveyor speed is controlled by an operator using a variable-resistance device (e.g., a rheostat). The rheostat forms part of a speed control circuit which controls the speed of an AC electric motor driving the conveyor via gears. The degree of toasting is set by appropriate adjustment of the rheostat. An increase in resistance causes the speed control circuit to decrease the conveyor speed, thereby increasing the degree of toasting. Conversely, a decrease in resistance of the rheostat causes an increase in conveyor speed, thereby decreasing the degree of toasting. The operator adjusts the rheostat setting such that the food product being processed is properly heated or toasted.
Despite having control circuits for controlling the conveyor speed and heating elements, such conveyor ovens are unable to control the degree to which food products are heated under certain conditions. For example, assume a speed control circuit is adjusted to lightly toast a given load of food products. If the conveyor drive moves too quickly; it will not be possible to toast the product properly because the food product will spend too much time by the doors or for instance if a large item is placed on the conveyor. During this period, food products being processed will receive an insufficient amount of heat energy and will be undercooked.
Attempted solutions to this problem have been to increase the power of the additional heating elements or to switch on more heating elements using the thermostat. These solutions, however, have several drawbacks. First, the higher power ratings or additional heating elements increases the cost of the ovens. Second, the additional power can result in over-heating or burning the products. Third, longer cooking times require a longer conveyor to move the product away from the input and output openings, thus increasing the cost and size of the toaster.
Accordingly, it would be advantageous to provide an improved feeding mechanism and speed control circuit for a conveyor oven. It would be advantageous to provide a feeder mechanism that automatically places the food onto the conveyor. It would further be advantageous provide a feeder and discharge mechanism which will automatically function to handle the food products and act a door for the toaster oven. It would also be advantageous to provide a simplified conveyor speed control circuit having decreased complexity, lower costs and increased reliability compared to computerized control circuits.
A main object of the present invention is to provide an electrical apparatus that allows one to insert bread slices into a feeder mechanism, which automatically opens during the first stage of a toasting sequence.
While a further object of the present invention is to provide a toasting apparatus that has a bigger access opening for communicating with other toaster items generally larger than a slice of bread. These items may include pizza rolls or dinner buns.
Still another object of the present invention is to provide a trip mechanism for starting the apparatus, and for alerting one that the toasting cycle has been completed and the apparatus has shut itself off.
Another object of the present invention is to provide a timer for use with placing the oven rack in a fixed position while stationary baking is needed.
In light of the foregoing problems with common household toasters, and to fulfill the above-stated objects, there is provided, according to one aspect of the present invention, a new and improved household toaster which utilizes a segmented conveyor for carrying items to be toasted through opposing upper and lower heating filaments. The toasted items are then discharged through an exit in the side of the device.
A first embodiment of the present invention comprises a generally trapezoidally shaped shell having a door at the forward wall area. Located at the side walls are a first opening, for inserting slices of bread, and a second opening for receiving the slice once the toasting cycle has been completed. (The first and second openings, include doors. The doors function as feeder and discharge mechanisms.)
A segmented chain conveyance mechanism, driven by sprocket axle attached to an electric motor, supports the items to be toasted and has an electronic controller for determining the conveyor speed. The slower the conveyor speed the longer the items remain between the heating filaments. This provides flexibility in the unit to provide longer cycle times for providing well done items or where longer cooling times per item is required. The control dial or electronic controller also regulates the timing and movement of the feeder and discharge mechanisms.
Also located along the front surface of the toaster is a timer and clock. The timer is activated by a dial which controls the conveyor speed. The clock is a convenience item for the user.
Extending from the rearward wall of the toaster of the present invention is a drive assembly. The assembly is electrical and runs on 110 volt household current. The assembly further comprises a variable speed electric motor housed in a separate shell to prevent toast debris from infiltrating the are a. Extending from the motor compartment, and transversing the conveyor segments, is a drive axle having sprockets which communicate with the individual conveyor segments to propel the assembly.